Delete CosmosDB entry using Azure Function

Question

I have been searching for a technique to use Azure Functions to delete items in a Cosmos database, using the in-browser code editor. Theres various reasons on my side why I dont want to use locally-developed code on VS.

The code I am using is available here, I am using a HttpTrigger with a CosmosDB input and output binding. They are named fairly obviously (inputDocument, outputDocument).

This code is working amazingly for reading items from the db, and writing new documents, however I want to be able to delete a single item. I'm making a game 'auction house' system, and to 'buy' an item, I need to remove it from the db.

I have searched a fair few places now, many people say to use DocumentDB, but I dont think browser-editor can support this, I cant get it to recognise the correct Azure libraries to be able to use this. If I'm missing a step, please let me know. Its failing when I add

#r "Microsoft.Azure.Documents.Client"
using Microsoft.Azure.Documents.Client;

EDIT After talking with Azure Support, I have found out that v3 uses Documents.Core, not Documents.Client. If anyone can supply docs for Documents.Core I will be thankful!

Thanks. Code copied below;

    #r "Newtonsoft.Json"

    using System.Net;
    using System.Linq;
    using Microsoft.AspNetCore.Mvc;
    using Microsoft.Extensions.Primitives;
    using Newtonsoft.Json;

    public class AuctionItem
    {
        [JsonProperty("itemID")]
        public string itemID { get; set; }
    
        [JsonProperty("price")]
        public string Price { get; set; }
    
        [JsonProperty("amount")]
        public string Amount { get; set; }
    }

    public static IActionResult Run(HttpRequest req, out object outputDocument, 
    IEnumerable<AuctionItem> inputDocument, ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");

        string name = req.Query["name"];
        string price = req.Query["price"];
        string amount = req.Query["amount"];

        string command = req.Query["command"];

        outputDocument = null;

        if (!string.IsNullOrEmpty(name) && !string.IsNullOrEmpty(price) && !string.IsNullOrEmpty(amount)) 
        {
            string responseMessage = "{\"Message\":\"Success\",\n\"Data\": [" + "\n";
               
            if (!string.IsNullOrEmpty(command)) {
                if (command == "1") {
                    foreach (var item in inputDocument) {
                        responseMessage += "{\n\t\"itemID\":\"" + item.itemID + "\"," + "\n";
                        responseMessage += "\t\"price\":\"" + item.Price + "\"," + "\n";
                        responseMessage += "\t\"amount\":\"" + item.Amount + "\"}," + "\n";
                    }
                } else if (command == "2") {
                    var item = inputDocument.Where(x => x.itemID == name).FirstOrDefault();
                    if (item != null) {
                        inputDocument = inputDocument.Where(x => x != item);
                    }
                } else if (command == "3") {
                    responseMessage += "{\n\t\"itemID\":\"" + name + "\",\n";
                    responseMessage += "\t\"price\":\"" + price + "\",\n";
                    responseMessage += "\t\"amount\":\"" + amount + "\"}\n";
                

                    log.LogInformation(responseMessage);
                    outputDocument = new {
                        itemID = name,
                        price = price,
                        amount = amount
                    };
                }
            }
        
            responseMessage += "]}";
            return new OkObjectResult(responseMessage);
        } else {
            outputDocument = null;
            return new BadRequestResult();
        }
            
    }

Answer 1

You need to create a file named "function.proj" in your http trigger.

Content:

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <TargetFramework>netcoreapp3.0</TargetFramework>
    </PropertyGroup>
    <ItemGroup>
        <PackageReference Include="Microsoft.Azure.DocumentDB.Core" Version="2.12.0" />
    </ItemGroup>
</Project>

Create step:

1.switch to classic experience

2.create file

Below is my test code, and it can work fine:

#r "Newtonsoft.Json"
#r "Microsoft.Azure.DocumentDB.Core"

using System.Net;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;
using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using System;
using System.Threading.Tasks;

private static DocumentClient client;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    client = new DocumentClient(new Uri("endpointUrl"), "authorizationKey");
    ResourceResponse<Document> response = await client.DeleteDocumentAsync(
        UriFactory.CreateDocumentUri("databaseName", "collectionName", "id"),
        new RequestOptions { PartitionKey = new PartitionKey("partition-key-value") });

    log.LogInformation("Request charge of delete operation: {0}", response.RequestCharge);
    log.LogInformation("StatusCode of operation: {0}", response.StatusCode);


    return new OkResult();    
}

By the way, you can find docs here.